oracle数据库中查询结果的列如何划分

Posted 2023-05-09

【中文标题】oracle数据库中查询结果的列如何划分

【英文标题】：how to divide the columns in result of query in oracle database

【发布时间】：2018-06-27 06:22:18

【问题描述】：

想要动态拆分查询结果中的列，我该怎么做？ 我有三个表并加入它们。以获取所需的列。

select distinct t1.sal,t1.cat,t2.id,t3.shop 
from t_table1 t1,
 t_table2 t2,
 t_table3 t3,

where t1.sno=t2.sno AND
t2.cat=t3.cat
t3.dept_no=t3.dept_no

**output:**

t1.sal  t1.cat  t2.id  t3.shop  
1900    34R5     10     dense    
1900    34r5     10     SVM
1900    34r5     10     bpo
2345    3ER4     11     kpo
2345    3ER4     11     infra
12345   34F4     12     const

**desired output:**

t1.sal  t1.cat  t1.tin  t2.id  t3.shop_1   t3.shop_2  t3.shop_3 
 1900    34r5   23456       10     dense       svm         bpo
 2345    3er4   6543        11      kpo        infra       null
 12345   34f4   34556       12      const       null       null

【参考方案1】：

使用PIVOT 和ROW_NUMBER 解析函数：

SQL Fiddle

Oracle 11g R2 架构设置：

CREATE TABLE your_query_result (sal, cat, id, shop ) AS
SELECT 1900,   '34R5',   10,   'dense' FROM DUAL UNION ALL
SELECT 1900,   '34r5',   10,   'SVM' FROM DUAL UNION ALL
SELECT 1900,   '34r5',   10,   'bpo' FROM DUAL UNION ALL
SELECT 2345,   '3ER4',   11,   'kpo' FROM DUAL UNION ALL
SELECT 2345,   '3ER4',   11,   'infra' FROM DUAL UNION ALL
SELECT 12345,  '34F4',   12,   'const' FROM DUAL;

查询 1：

SELECT sal,
       cat,
       id,
       "1_SHOP" AS shop_1,
       "2_SHOP" AS shop_2,
       "3_SHOP" AS shop_3
FROM   (
  SELECT r.*,
         ROW_NUMBER() OVER (
           PARTITION BY sal, cat, id
           ORDER BY shop
         ) AS rn
  FROM   (
    SELECT * FROM your_query_result
  ) r
)
PIVOT (
  MAX( shop ) AS shop
  FOR rn IN ( 1, 2, 3 )
)

Results：

|   SAL |  CAT | ID | SHOP_1 | SHOP_2 | SHOP_3 |
|-------|------|----|--------|--------|--------|
|  1900 | 34R5 | 10 |  dense | (null) | (null) |
|  1900 | 34r5 | 10 |    SVM |    bpo | (null) |
|  2345 | 3ER4 | 11 |  infra |    kpo | (null) |
| 12345 | 34F4 | 12 |  const | (null) | (null) |

如果您希望第一行和第二行位于同一行，只需在生成ROW_NUMBER 和PIVOTing 之前将CAT 列更改为小写即可。